(a) Technical Field
The present disclosure relates to an environmental-friendly vehicle, and more particularly, to a failsafe device and a control method for a vehicle, through which a vehicle can drive on a limp home mode by producing temporally hydraulic pressure when an oil supply device and surrounding systems fail.
(b) Background Art
Generally, various ways have been used for supplying engine oil to an automatic transmission. In an existing vehicle of an internal combustion engine, a mechanical oil pump is operated by engine power to supply oil to the automatic transmission and to produce a predetermined oil pressure, thereby enabling shift. For a hybrid vehicle driven with a motor and engine power, a mechanical oil pump driven with engine power and an electric oil pump driven with a motor are connected in series wherein a proper hydraulic pressure is produced to operate the mechanical oil pump when a vehicle is driven with engine power, and the electric oil pump operates when the vehicle is driven with a motor, thereby enabling shift.
However, the electric oil pump may not be used when the oil pump and oil supply system fail, and thus the mechanical oil pump is driven using a motor to produce and maintain oil pressure, thereby enabling a minimum driving of a vehicle. This function refers to as a failsafe in which a safe device operates to prevent an accident even when a part of some apparatus or systems has failed or is mal-operated. Additionally, a limp home driving generally refers to an emergent driving in which the mechanical oil pump is driven to fix generally refers to an emergent driving in which the mechanical oil pump is driven to fix shifting stage when the electric oil pump fails, and which enables at least minimum driving for the vehicle to arrive at a repair location.
This limp home driving has been disclosed in the related art. Specifically, a limp home control method for a hybrid vehicle has been disclosed for a hybrid vehicle that uses a mechanical oil pump and an electric oil pump simultaneously, when the electric oil pump and the surrounding systems fail, hydraulic pressure is produced temporally using a motor to drive a vehicle.
FIG. 1 is an exemplary diagram showing a failsafe device for a vehicle according to a related art wherein a mechanical oil pump 50 and an electric oil pump 40 are connected to a transmission 10 via the respective oil channels to provide hydraulic pressure necessary for the transmission 10 based on the control of an oil pump controller (OPU) 30 that is operated by a transmission controller (TCU) 20, and when the electric oil pump 40 fails, the mechanical oil pump 50 supplies oil to the transmission 10, to provide the necessary oil pressure.
However, the mechanical oil pump is not installed to decrease structure and weight of a vehicle to improve fuel ratio and it converts into a system in which only the electric oil pump is driven wherein when the electric oil pump and the oil pump controller fail, the necessary hydraulic pressure is not provided to the transmission thus preventing the vehicle from being driven.
The description provided above as a related art of the present invention is just for helping understanding the background of the present invention and should not be construed as being included in the related art known by those skilled in the art.